Conventionally, there has been a problem associated with control of a chip flow direction in various cutting processes (refer to Patent Documents 1 to 3). Particularly, as shown in FIG. 1, the control of chip flow direction is a significant problem with a cutting insert 1′ for a grooving process of grooving an end surface of a columnar workpiece 100′ by rotating the workpiece 100′ in Y1′ direction. Specifically, it is significant that a chip discharge direction is a direction parallel to a feed direction of a cutting tool (a direction indicated by a white arrow in FIG. 1) during the grooving process as shown in FIG. 1. If the chip discharge direction is a direction perpendicular to the feed direction of the cutting tool (a direction indicated by a black arrow in FIG. 1), chips may come into contact with the end surface of the workpiece without being discharged to the outside, thus causing chip clogging.
The cutting insert for the grooving process preferably brings chips into a continuous helical shape than finely cutting the chips. When the chips are finely cut and discharged, the chips may scatter somewhere on the end surface of the workpiece, thus increasing the possibility of chip clogging. However, if it is possible to discharge chips in a continuous shape, the chips are less likely to come into contact with the end surface of the workpiece, thereby reducing the possibility of chip clogging. Hence, a significant problem associated with the cutting insert for the grooving process is how to control chips so as to flow the chips in the direction parallel to the feed direction.
The present invention has been made in view of the above problems, and aims at providing a cutting insert having excellent chip discharge performance.
Patent Document 1: Japanese Unexamined Patent Publication No. 2008-272923;
Patent Document 2: Japanese Unexamined Patent Publication No. 9-174308; and
Patent Document 3: Japanese Unexamined Patent Publication No. 2001-322010